This is the sun as it appeared on May 13, 2022. The large, dark region is sunspot AR 3008:

Sunspots are formed as a result of the Sun’s complex magnetic field interacting with its plasma. The Sun’s magnetic field is generated by the motion of charged particles within its core, creating a dynamo effect. This magnetic field extends outwards and becomes twisted due to the Sun’s differential rotation – faster at the equator and slower at the poles.

These twisted magnetic fields can sometimes become concentrated in certain areas, causing a localized increase in magnetic pressure. As a result, this increased pressure inhibits the flow of hot plasma from the Sun’s interior to its surface in those regions. Consequently, these areas experience a drop in temperature compared to their surroundings, appearing darker and thus forming sunspots.

Sunspots typically occur in pairs or groups with opposite magnetic polarity. They have an umbra – the darkest central region – surrounded by a lighter penumbra. The size and number of sunspots vary over time, following an approximately 11-year cycle known as the solar cycle. During periods of high solar activity, sunspot numbers increase and can lead to various space weather phenomena such as solar flares and coronal mass ejections (CMEs).